New owner - 1.48 Ma drain, stumped. - Mercedes-Benz Forum

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post #1 of 2 (permalink) Old 03-10-2014, 07:06 AM Thread Starter
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Date registered: Jan 2014
Vehicle: 2003 ML320
Location: VA, USA
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New owner - 1.48 Ma drain, stumped.

Hi all - purchased an '03 ML320 a month back. Love the thing- looks great and a true pleasure to drive. Love the wealth of knowledge on the forum.

That said, having a tough time diagnosing a parasitic drain. Bear with me as I've done a fair share of research. Since I'd like to get it off life support (battery tender) I wanted to run you all by my issues before outlaying further money/time. Let me take you through the series of events:

Facts: '03 with 70k. CD changer, no Navi. Previous owner had everything done at MB dealer, although service department wont give me a copy service history I did scan through the sheet at the dealer and saw that the car was towed in and the "ground strap" was replaced. Alternator is solid, reads 14+ volts when car is running.

-After owning the car for a few weeks, the battery was dead. Wasn't sure how old the previous battery was so I replaced.

-Week or so later - dead. Searched the hell out of the forums. Performed a fuse (and relay) pull, no drops in amps. Additionally, threw BAS ESP light (stayed on after turning the wheel back and forth to reset the SAS).

-Took to local Benz specialist. They noted that the BAS light was thrown due to issues in SAS circuit. Additionally, fuse 13 was missing and that upon replacement, the draw increased. This indicated that the parasitic drain likely existed before my ownership and the previous owner pulled this fuse to fix the problem temporarily. Ultimately determined that replacement of the AAM was necessary ($1000 after diag/labor).

-Few days later, dead again. Currently 1.48 mA draw per my meter on the mA scale. Will pull fuses yet again, however I feel like I'm beating a dead horse. Circuit 13 does not register a drop in amps when pulled.

A few thoughts - Wiring issues between battery/alternator/starter/ground. Ground points look good in appearance, however due to the service history (new ground strap), perhaps the issue could be there. CAN BUS issues? CD changer? Any glaring oversights on my part?
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post #2 of 2 (permalink) Old 03-10-2014, 07:46 PM
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Date registered: Dec 2012
Vehicle: 87 560SL, 71 280SL euro, 74 VW Ghia, 78 280Z Black Pearl, 78 280Z, 04 Corolla, 07 Odyssey, 94 Prizm
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Something is staying on in the vehicle. Have you checked all the fuses? I once had a C230 Kompressor that had a drain and it had a GPS tracking device that went bad (will never show up on the wiring diagrams). Pull the fuses one at a time to see how much voltage drop it has. Now, these vehicles have networking. If you wake up the network, it will cause a draw until the network "falls asleep", when no modules are communicating. I don't know much on current draws on these vehicles, but with the amp meter, remove the connector behind the ignition switch and allow some time to pass to see if it falls asleep. It could be a bad ignition switch. The switch is not expensive. It is like 20-30 dollars at the dealer.

"The grass is greener...where you water it!"
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1972 280se 4.5 white w/ red leather
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1978 Datsun 280Z "Black Pearl"
1978 Datsun 280Z (CLK430 swap)
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